Field of the Invention
The invention relates to a nuclear reactor installation, in particular for light water reactors, with a reactor pressure vessel having a reactor core and a core catcher device.
Such a nuclear reactor installation is known from U.S. Pat. No. 3,607,630. In addition, that known nuclear reactor installation has the following features: a supporting and protective structure delimits a reactor cavern with a bottom region and a circumferential wall, and the reactor pressure vessel, disposed in the reactor cavern at vertical and lateral distances in relation to the bottom region and the circumferential wall, is seated in the supporting and protective structure. In that case the core catcher device has a collecting basin for the core melt, which can be cooled by means of a coolant and is embedded within the reactor cavern and below the reactor pressure vessel in the bottom region of the supporting and protective structure. The collecting basin, which is also known as a "core catcher", is flat, pan-shaped and water-cooled internally. It is connected through an ascending pipe to a flood container disposed at a higher level. The wet steam forming in a hypothetical case of a core melt, i.e. when the core melt is distributed in the collecting basin, is blown off through outlet lines into the containment vessel or into condensation devices (steam separators). The condensed cooling water is returned to the flood container. The collecting basin is formed of a plurality of parallel tubes connected at the respective inlet and outlet ends to a common distribution or collection tube. However, the relatively good cooling properties of such a known collecting basin can be impaired, particularly in the case of nuclear reactors with higher output, if the tube structure of the collecting basin is deformed by large falling masses and the cooling cross sections are reduced or blocked by thereby.
The core catcher according to Published UK Application No. GB 2 236 210 A, has a collecting basin in "multilayer sandwich construction", with a bearing, downwardly arched steel pot, cladding of interlocked zirconium blocks and a steel skin covering the cladding at the top, which melts through in the case of an impacting core melt, i.e. it is sacrificed. Since the catch volume of the core catcher is relatively small and, alternatively to gas cooling, is only provided with a standing water column in the shield pit or reactor cavern, effective continuous cooling of the core melt (which in the beginning may have temperatures above 2000.degree. C.) would only be possible with small reactor outputs, since otherwise film boiling could occur at the outer steel jacket of the core catcher, along with the danger of considerably reduced heat transfer.